With the advent of modern study and treatment of biological systems, there has arisen an increasing need for monitoring of the internal state of biological systems that is either non-invasive or is minimally invasive. For example, micro-endoscopes and catheter-based ultrasound probes have been developed to produce images of the interior of organisms. Many other technologies have been developed to measure the physiological and anatomical features of the biological system in question. These technologies have proven invaluable in the diagnosis and treatment of such systems.
It is desirable, therefore, to perform thermal imaging of biological systems in a minimally invasive manner as well. Such imaging would make possible real-time three-dimensional thermal mapping, allowing both researchers and medical personnel to study the micro-metabolic functioning of cell and tissue systems in-situ, i.e., in actually functioning biological systems. Such imaging could provide to such personnel otherwise presently unavailable information about the actual metabolic functioning of the biological system in question.
In addition, such thermal mapping could prove invaluable in assessing in real-time the effects of sample exposure to a highly focused laser beam during both diagnostic and therapeutic treatment. Given the increasing reliance on the use of such lasers in both diagnostic and therapeutic treatment, such imaging could become an important method of critically assessing the ongoing treatment and for avoiding unintended thermal damage to the tissue.
Further, such monitoring may facilitate the development of new thermal techniques for the diagnosis and treatment of the tissues in question. For example, temperature-sensitive liposomes have been used in combination with the inducement of local hyperthermia or hypothermia (see for example, M. B. Yatvin, I. M. Tegmo-Larsson and W. H. Dennis, "Temperature and pH-Sensitive Liposomes for Drug Targeting", Methods in Enzymology, Vol. 149 (1987), pp. 77-87). The availability of in-situ thermal monitoring will undoubtedly lead to additional diagnostic and therapeutic treatment that cannot yet be foreseen.
In addition, there are a wide range of systems other than biological systems for which; microthermometry would be advantageous. For example, it may be desirable to measure temperatures in-situ in a variety of fluidic media, such as water, gasoline, and solvents. Again, the availability of such imaging would clearly be advantageous in additional ways yet unforeseen.
There have therefore been a number of attempts to provide techniques for the measurement of temperature, temperature changes and heating effects in dielectric and organic samples. Such techniques previously attempted include laser-induced fluorescence, Raman spectroscopy, photochemical absorption spectroscopy, and Zeeman interferometry. These techniques have proven either to be limited by poor spatial, temporal, or thermal resolution, or are difficult to adapt to in-situ use in biological or other systems.
Hence, it would be advantageous to develop a high resolution sensor designed for use in-situ in biological systems. Such a sensor should ideally be organically compatible with the surrounding tissue to avoid reactions therewith which would be both disruptive of the accurate measurement of temperature and normal metabolic function as well as potentially damaging to the tissue being observed. Such a sensor should additionally be easily manipulated using conventional technology.